There are existing devices that can concentrate incoming electromagnetic waves, such as light and telecommunication signals, to their respective focal points when the electromagnetic waves fall normal to their apertures. Such devices have been used for a long time in Solar Energy Concentration to concentrate solar beams on the focal point and in telecommunication to concentrate the signal to the receiver device at the focal point.
In solar applications, the concentrating reflecting solar parabolic dish and concentrating lens have many important characteristics, such as high concentration resulting in a very high receiver temperatures or a high Photovoltaic (PV) efficiency. Similarly, a lens (either smooth or Fresnel lens) can be used to concentrate light and solar beams to the focal point. There are available commercial products in the market where the Parabolic Dish tracks sun automatically and the resulting high temperature is used to operate a Sterling Engine for example or to concentrate the sun on a CPV (Concentrating Photo Voltaic). In some cases the high temperature can be used to melt metals at the receiver.
The receiver has to move as the dish or lens changes its angle to track the signal or the sun. Similarly, this is the case in all solar concentrating lenses where the focal point in all existing devices changes position as the lenses track the sun. This imposes many limitation to the applications of the Parabolic Dish or lens concentrators especially if the receiver is heavy or has to have flow of materials to it and (or) from it. In Solar Parabolic Dish Concentrators, for example, the sterling engine weight is a major constrain along with the wind load which limit the capacity of the largest existing Solar Parabolic Dish electricity generation to 25 KW.
A complicated tracking mechanism is needed to concentrate the solar beam or the signal to a focal point fixed to the ground. One attempt in solving this issue was by having a linear collector fixed to the ground with pivoting concentrator that change in angle. However, in that prior art the focal point keep changing along the receiver. Some prior arts teach about tracking devices where the parabolic dish rotates around a fixed platform to the ground. Although various electromagnetic wave front concentrators are known to the art, all, or almost all of them suffer from one or more than one disadvantage. All of these devices have a focal point that is moving as the dish or the lens track the sun. Therefore, there is a need to provide methods and apparatus for fixing the focal point to the ground while tracking and concentrating the incoming waves.
The present invention illustrates a method and apparatus for tracking and concentrating electromagnetic waves coming from a moving source at a focal point fixed to the ground. The invention discloses a tracking system for a device capable of concentrating incoming electromagnetic waves at a fixed focal point. One embodiment of such invention is used for tracking and concentration of incoming solar waves.